On my quiz submission today, i got a disconcerting message.

"Warning: It appears that your answer might be something similar to "All of these" or "None of these". We discourage this type of question. Please try to write questions where each answer stands alone and does not reference other answer choices."

However, the answer which probably provokes this caveat is an answer containing the word "ball", not "all".

I suppose the code to detect the presence of phrases such as "all of these" or "none of these" is a bit too strict in handing out a warning if the letter combination "all" (or "none") as PART of a word appears in one of the answers.

I've no objection that the system warns if one of the answers contains the word "all" or "none" (as independent word, not as part of the word). But in my dictionary, a "ball" is not the same as "all".

Yes, the system does treat occasions like this as the question having "all" in it. And in this situation, you can ignore the warning. It might be disconcerting the first time you see it, but the system doesn't disallow you to submit, so it's a false positive that editors will ignore as well.

I'd already noticed that the warning did not prevent submission. If ever Terry finds some time, maybe he'll find a way to finetune this control.

Yes, it could certainly use some fine-tuning.